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Choosing a Data Modeling Technique
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Choosing a Data Modeling Technique

MediumSQL · PostgreSQL

Problem

Can you describe a scenario where you would choose a specific data modeling technique over another?

Using the supplied schema, write a query that produces an analytics-ready monthly revenue result. The query should include completed orders only and handle customers without a populated segment.

Output

  1. One row per customer segment and calendar month
  2. Columns: segment, revenue_month, completed_orders, revenue
  3. Include only segments with completed revenue, order by segment ascending and revenue_month ascending

Schema

customers
ColumnTypeDescription
customer_idPKINTUnique customer identifier
segmentVARCHAR(30)Customer reporting segment
orders
ColumnTypeDescription
order_idPKINTUnique order identifier
customer_idINTCustomer associated with the order
order_dateDATEDate the order was placed
statusVARCHAR(20)Current order status
order_items
ColumnTypeDescription
order_item_idPKINTUnique order item identifier
order_idINTOrder containing the item
product_nameVARCHAR(80)Name of the purchased product
quantityINTUnits purchased
unit_priceNUMERIC(10,2)Price per unit
Tablescustomersordersorder_items
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